Relax redis dependency requirements and fix NPE in Redis tracing
Allow calling applications more flexibility on the version of redis-rb
that they use.
Required for https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/30238
This change also resolves a bug discovered when integrating this change into gitlab-ce, whereby some arguments appear to be nil, leading to NPEs in the application when tracing is enabled.
Edited by Andrew Newdigate